The present invention relates to an ice thermal storage type air conditioner in which ice making or thawing is effected by causing a refrigerant to flow in a heat transfer tube provided in an ice thermal storage tank and, more particularly, to an ice thermal storage type air conditioner suitable to increase the productivity of the ice thermal storage tank.
Conventionally, a technology has been known in which fins are provided so as to fill a clearance between heat transfer tubes forming a heat exchanger in the ice thermal storage tank, and a space that has not been used effectively for ice making is used, by which the ice packing factor is increased. Such a technology has been disclosed in JP-A-7-332711, for example. Also, JP-A-64-10081 has disclosed a technology in which a panel type ice making coil is filled in an ice thermal storage tank so that ice is made into a panel shape, by which water is prevented from being confined in the process of ice making, and the breakage of a heat transfer tube is prevented.
In the aforementioned prior art described in JP-A-7-332711, because the fins are provided in the horizontal direction of the heat transfer tube, the convection of water is hindered in the ice thermal storage tank at the time of ice making. Therefore, the confinement of water occurs, so that there is the possibility that the confined ice freezes at the time of icing and expands, resulting in the breakage of the heat transfer tube.
Also, the aforementioned prior art described in JP-A-64-10081 proposes an ice thermal storage type air conditioner opposed to an external melt type in which air conditioning is performed by circulating water at the time of thawing. For the ice thermal storage type air conditioner of a complete internal melt type in which the ice thermal storage tank is handled as a part of condenser at the time of thawing, the heat transfer tube of an ice making heat exchanger also has a high pressure. For the ice thermal storage type air conditioner using a non-azeotropic mixture refrigerant, a stronger pressure-resisting heat transfer tube is needed. For the panel type ice making coil, improper joining and corrosion of the joint portion, leakage of refrigerant, or entrance of water into a refrigerating cycle must be considered.
Further, the panel type ice making coil must be formed specially, so that the coil of this type cannot be said to be suitable for the decrease in cost. Further, it must be manufactured from the beginning so as to match the size of the ice thermal storage tank, so that there is a problem in terms of common use and flexibility, etc.
The present invention has been made to solve the problems with the aforementioned prior arts, and an object thereof is to provide an ice thermal storage tank and an ice thermal storage type air conditioner, in which the ice packing factor is increased, the leakage of refrigerant or the entrance of water into the refrigerating cycle is prevented, the reliability is enhanced even when a non-azeotropic mixture refrigerant, a natural refrigerant, or the like is used, and a low cost is achieved.
The present invention solves at least one of the aforementioned problems.